US2007085465A1PendingUtilityA1
Color cathode-ray tube
Assignee: MATSUSHITA TOSHIBA PICTUREPriority: Oct 13, 2005Filed: Aug 30, 2006Published: Apr 19, 2007
Est. expiryOct 13, 2025(expired)· nominal 20-yr term from priority
H01J 2229/0794H01J 29/07
48
PatentIndex Score
0
Cited by
0
References
0
Claims
Abstract
A shadow mask includes a perforated region in which a plurality of electron beam passage apertures are formed, a non-perforated region on the periphery of the perforated region, and a skirt portion bent to an electron gun side with respect to the non-perforated region. The curved surfaces on an x-axis and a y-axis of the perforated region are convex to a panel side. The perforated region includes a curved surface that is convex to the panel side and a curved surface that is convex to the electron gun side on a periphery of the perforated region. Furthermore, the perforated region has a curved surface that is convex to the panel side and a curved surface that is convex to the electron gun side in a region surrounded by the periphery, the x-axis, and the y-axis. Because of this, the color displacement caused by doming can be reduced while a shadow mask is used which is made of an inexpensive iron material, and in which the increase in the difference in elevation in the z-axis direction between a center portion and a diagonal portion of the perforated region is suppressed.
Claims
exact text as granted — not AI-modified1 . A color cathode-ray tube, comprising: a panel; a funnel connected to the panel; an electron gun provided in a neck of the funnel; and a substantially rectangular shadow mask provided so as to be opposed to an inner surface of the panel,
wherein the shadow mask includes a perforated region in which a plurality of electron beam passage apertures are formed, a non-perforated region provided on a periphery of the perforated region, in which the electron beam passage apertures are not formed, and a skirt portion bent to the electron gun side with respect to the non-perforated region, and assuming that a center of the perforated region is an origin, an axis that passes through the origin and is parallel to a long side of the shadow mask is an x-axis, an axis that passes through the origin and is parallel to a short side of the shadow mask is a y-axis, and a normal to the shadow mask at the origin is a z-axis, curved surfaces on the x-axis and the y-axis in the perforated region are convex to the panel side, the perforated region has a curved surface that is convex to the panel side and a curved surface that is convex to the electron gun side on a periphery thereof, and the perforated region has a curved surface that is convex to the panel side and a curved surface that is convex to the electron gun side in a region surrounded by the periphery, the x-axis, and the y-axis.
2 . The color cathode-ray tube according to claim 1 , wherein a direction directed from the shadow mask to the electron gun is set to be a positive direction of the z-axis,
assuming that z-coordinates of two points on a surface of the perforated region, which have the same y-coordinate and x-coordinates of x 1 and x 2 , are z 1 and z 2 , respectively, and x 1 <x 2 , a relationship z 1 <z 2 is satisfied, and assuming that z-coordinates of two points on the surface of the perforated region, which have the same x-coordinate and y-coordinates of y 3 and y 4 , are z 3 and z 4 , respectively, and y 3 <y 4 , a relationship z 3 <z 4 is satisfied.
3 . The color cathode-ray tube according to claim 1 , wherein a z-coordinate of a point on a surface of the perforated region is, with an x-coordinate of the point being a variable x, represented by an m-order function of the variable x on the x-axis, represented by a cosine function of the variable x on a long side of the perforated region, and represented by a function including at least the m-order function of the variable x and the cosine function of the variable x in a region between the x-axis and the long side.
4 . The color cathode-ray tube according to claim 1 , wherein a z-coordinate of a point on a surface of the perforated region is, with a y-coordinate of the point being a variable y, represented by an n-order function of the variable y on the y-axis, represented by a cosine function of the variable y on a short side of the perforated region, and represented by a function including at least the n-order function of the variable y and the cosine function of the variable y in a region between the y-axis and the short side.
5 . The color cathode-ray tube according to claim 1 , wherein a z-coordinate of a point on a surface of the perforated region is, with an x-coordinate and a y-coordinate of the point being a variable x and a variable y, represented by an m-order function of the variable x on the x-axis, represented by an n-order function of the variable y on the y-axis, represented by a cosine function of the variable x on a long side of the perforated region, a cosine function of the variable y on a short side of the perforated region, and represented by a function including at least the m-order function of the variable x, the n-order function of the variable y, the cosine function of the variable x, and the cosine function of the variable y in a region surrounded by the x-axis, the y-axis, the long side, and the short side.
6 . A color cathode-ray tube according to claim 1 , wherein assuming that an x-coordinate of a point where a pair of short sides of the perforated region and the x-axis cross each other is ±X P , a z-coordinate thereof is Z XP , a y-coordinate of a point where a pair of long sides of the perforated region and the y-axis cross each other is ±Y P , a z-coordinate thereof is Z YP , and a z-coordinate of a point where a periphery of the perforated region and a diagonal axis of the perforated region cross each other is Z DP (X P , Y P , Z XP , Z YP , Z DP ≠0), a z-coordinate of an arbitrary point on the surface of the perforated region is approximated by the following Expression 1 with an x-coordinate and a y-coordinate of the point being variables x and y
z
(
x
,
y
)
=
γ
[
α
z
x
1
(
x
)
+
{
1
-
α
}
z
x
2
(
x
)
]
+
z
y
1
(
y
)
,
α
=
1
2
{
1
+
cos
(
π
Y
P
)
}
,
γ
=
1
+
z
yS
(
y
)
-
z
y
1
(
y
)
Z
XP
,
z
x
1
(
x
)
=
ax
m
,
a
=
Z
XP
X
P
m
,
m
≥
0
,
z
x
2
(
x
)
=
b
{
1
-
cos
(
π
X
P
x
)
}
,
b
=
1
2
Z
XP
,
z
y
1
(
y
)
=
cy
n
,
c
=
Z
XP
Y
P
n
,
n
≥
0
,
z
yS
(
y
)
=
d
{
1
-
cos
(
π
Y
P
y
)
}
,
d
=
1
2
(
Z
DP
-
Z
XP
)
.
Expression
1
:
7 . The color cathode-ray tube according to claim 6 , wherein in the Expression 1, Z x2 (x) is represented by
z
x
2
(
x
)
=
b
[
1
-
∑
λ
=
1
h
{
R
1
λ
cos
(
λ
π
X
P
x
)
}
+
C
1
]
(
R
1
λ
:
Constant
with
respect
to
each
λ
.
C
1
:
Constant
)
where a term of a cosine function is replaced with a cosine series.
8 . The color cathode-ray tube according to claim 6 , wherein in the Expression 1, α is represented by
α
=
1
2
[
1
+
∑
μ
=
1
i
{
R
2
μ
cos
(
μ
π
Y
P
y
)
}
+
C
2
]
(
R
2
μ
:
Constant
with
respect
to
each
μ
.
C
2
:
Constant
)
where a term of a cosine function is replaced with a cosine series.
9 . The color cathode-ray tube according to claim 6 , wherein in the Expression 1, Z yS (y) is represented by
z
yS
(
y
)
=
d
[
1
-
∑
ν
=
1
j
{
R
3
ν
cos
(
ν
π
Y
P
y
)
}
+
C
3
]
(
R
3
ν
:
Constant
with
respect
to
each
ν
.
C
3
:
Constant
)
where a term of a cosine function is replaced with a cosine series.
10 . The color cathode-ray tube according to claim 1 , wherein the non-perforated region connects the perforated region to the skirt portion with a smooth curve in a cross-section that is parallel to the z-axis and vertical to a plane of the skirt portion, and a radius of curvature of the non-perforated region is maximum in a diagonal direction passing through a diagonal axis end of the shadow mask.
11 . The color cathode-ray tube according to claim 1 , wherein the non-perforated region has a linear portion in a cross-section that is parallel to the z-axis and is vertical to a plane of the skirt portion.
12 . The color cathode-ray tube according to claim 1 , wherein the shadow mask is made of a material containing Fe as a main component.
13 . The color cathode-ray tube according to claim 1 , wherein the shadow mask has an electron reflective coating film on a surface thereof opposed to the electron gun.
14 . The color cathode-ray tube according to claim 1 , wherein the perforated region has a plurality of tie-bands with a longitudinal direction thereof being the y-axis direction, and unevenness is formed by half-etching on surfaces of the plurality of tie-bands.Join the waitlist — get patent alerts
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